Shoe sole

Abstract

The present invention relates to a shoe sole that includes a polyamide in the form of powder or microfibers admixed with a thermoplastic base material to improve the strength, durability, abrasion resistance, and other desirable physical properties of the shoe sole. Suitable thermoplastic base materials include rubber, polyurethane or ethylene vinyl acetate. The polyamide microfibers are randomly and nonuniformly oriented to reinforce the shoe sole in all directions.

What is claimed is:  
     
       1. A shoe sole comprising, a thermoplastic base material formed in the shape of the shoe sole and containing therein an additive component comprising polyamide microfibers, polyamide powder, or mixtures thereof, wherein the additive component is present in an amount of about 0.5 to about 20 weight percent of the shoe sole. 
     
     
       2. The shoe sole of  claim 1  wherein the additive component comprises polyamide microfibers. 
     
     
       3. The shoe sole of  claim 1  wherein the polyamide microfibers are present in an amount of less than 5 weight percent of the shoe sole. 
     
     
       4. The shoe sole of  claim 1  wherein the additive component comprises polyamide microfibers having a length of about 0.05 mm to about 0.2 mm and a diameter of less than about 0.015 mm. 
     
     
       5. The shoe sole of  claim 3  wherein the polyamide microfibers have a random orientation. 
     
     
       6. The shoe sole of  claim 1  wherein the thermoplastic base material is selected from the group consisting of polyurethane, rubber, and ethylene vinyl acetate. 
     
     
       7. The shoe sole of  claim 1  further comprising a binding agent in an amount sufficient to assist in retaining the additive component in admixture with the thermoplastic base material. 
     
     
       8. The shoe sole of  claim 1  wherein the thermoplastic base material and the additive component contained therein are homogenously or partially homogenously blended. 
     
     
       9. A shoe comprising an upper and the shoe sole of  claim 1  as a midsole. 
     
     
       10. A shoe comprising an upper and the shoe sole of  claim 1  as a lower, surface contacting sole. 
     
     
       11. A process for making a shoe sole comprising a thermoplastic base material and an additive component mixed therein, the process comprising, admixing at least one thermoplastic base material and an additive component comprising polyamide microfibers, polyamide powder, or mixtures thereof, wherein the additive component is present in an amount of about 0.5 to about 20 weight percent of the shoe sole; heating the admixture of the thermoplastic base material and the additive component; and forming the admixture in the shape of a shoe sole. 
     
     
       12. The process of  claim 11  wherein the admixture is heated to a temperature below the melting point of the additive component to form a partially homogenous blend. 
     
     
       13. The process of  claim 11  wherein the admixture is heated to a temperature above the melting point of the additive component to form a homogenous blend. 
     
     
       14. The process of  claim 11  further comprising adjusting the temperature and the quantities of the thermoplastic base material and the additive component to obtain desired physical properties of the shoe sole. 
     
     
       15. A shoe sole comprising, a thermoplastic base material formed in the shape of the shoe sole and polyamide microfibers contained in the thermoplastic base material, wherein the polyamide microfibers are present in an amount of about 0.5 to about 20 weight percent of the shoe sole, and the polyamide microfibers have a length of about 0.05 mm to about 0.2 mm and a diameter of less than about 0.015 mm. 
     
     
       16. The shoe sole of  claim 15  wherein the polyamide microfibers have a length of about 0.1 mm to about 0.15 mm. 
     
     
       17. The shoe sole of  claim 15  wherein the polyamide microfibers are present in an amount of less than 5 weight percent of the shoe sole. 
     
     
       18. The shoe sole of  claim 15  wherein the polyamide microfibers have a random orientation. 
     
     
       19. The shoe sole of  claim 15  further comprising a binding agent in an amount sufficient to assist in retaining the polyamide microfibers in admixture with the thermoplastic base material. 
     
     
       20. The shoe sole of  claim 15  wherein the thermoplastic base material and the polyamide microfibers are homogenously or partially homogenously blended.